<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
    <script type="text/javascript">这里面的代码是js代码</script>
    <script>默认为js代码，这里面的代码是js代码</script>
    <script>alert('hello javascript')</script>
</head>
<body>
    <h1>JavaScript</h1>
    <input type="button" name="" value="提交" onclick="alert('hello HTML')">
</body>
</html>